This research project involves the chromatographic analysis of melanoma patient urines to detect, by means of a unique colorimetric reagent, diphenylpicrylhydrazyl (DPPH), the DOPA-derived intermediates of melanin synthesis. A number of common urinary constituents, such as uric acid, HIAA, and creatinine, are also detected, and serve as internal elution markers. The chromatographic pattern of metabolites is used to detect the early spread of occult metastatic disease, including vanillactic acid, 3-methoxytyrosine, and 2-S-cysteinyldopa, as well as three additional peaks, as yet unidentified, that are not pigment-related, and that also appear in the urine of patients with metastatic disease from other categories of cancer. The latter peaks do not correspond to the other known cancer markers, such as polyamines or t-RNA-derived nucleosides. The identification of these compounds is under investigation by GC/MS analyses.